The present invention relates generally to the art of railway cars. More particularly, the invention pertains to anti-drift retarders for gear operated plug-type doors for railway cars.
The invention is particularly applicable to plug-type metal doors of the type used on railway freight cars and will be particularly described with reference thereto. However, it will be appreciated by those skilled in the art that the invention has broader applications and is adaptable to use on doors of other types and in other environments.
Rectangular metal doors of a known type used in railway cars include a generally rectangular frame generally comprised of top, bottom, horizontal stiffeners, and opposed side members. Metal panels are secured to these frame members for completing the basic door construction. In most conventional railway cars, the frame members and metal panels are riveted and/or welded together.
Railway car doors are typically classified as either sliding doors or plug doors. Of the two, sliding doors are less complex, merely having a door configured to slide back and forth within a side panel of a railway car to selectively open and close an opening defined therein. Plug doors are more complex in that they are configured to first move laterally outward from the opening defined in the railcar, and then move longitudinally along a track disposed adjacent the railcar side panel. The present invention finds particular application to plug-type doors. However, it should be understood that the concept involved is equally applicable to other environments where selective movement of large doors between open and closed positions is required.
Plug doors to be mounted on the side of a railcar typically include a series of panels or sheeting reinforced by horizontally disposed channels at the top, bottom and intermediate portions of the door. A pair of vertically oriented elongated support members such as pipes, rods or bars are configured to support the door on the railcar. The support members are typically provided with upper and lower cranks attached to the ends thereof which serve as lever arms for laterally moving the door into and out of the railcar door opening. Upon actuation of a driving means, such as a manually operated gear assembly, the support members are rotated for causing corresponding rotation of the cranks. Rotation of the cranks, in turn, draws the door laterally outward from the door opening until the door is supported on a track disposed adjacent the side of the railcar. The door is moveably supported on the track by roller hangers which enable the door to slide longitudinally along the side of the railcar.
One problem that occurs when the door is drawn or moved onto the track is that the support members have a tendency to rotate, thus causing the door to drift back into the side of the railcar. If this occurs, the ability of the door to slide longitudinally along the track may be inhibited. Furthermore, the door or the side of the railcar may become damaged because of the drifting action.
Accordingly, it has been considered desirable to develop an anti-drift retarding device for a gear-operated do or that addresses the foregoing difficulties and others while providing better and more advantageous overall results.
In accordance with the present invention, an anti-drift retarder for a gear-operated door is advantageously provided.
The retarder is particularly suited for use with a railcar door assembly comprised of at least one sheet member having a front surface, channels laterally disposed on the front surface of the sheet member, and a pair of elongated support members rotatably mounted to the channels via a mounting mechanism. Each support member includes a first rotatable member attached to a support member first end, and a second rotatable member attached to a support member second end. A drive mechanism is operably connected to the pair of elongated support members for selectively imparting rotational movement thereto. A retarder assembly for preventing movement of the drive mechanism is mounted on the sheet member adjacent the drive mechanism.
The first and second rotatable members may each comprise a crank with a roller assembly attached at one end thereof. The rollers, in turn, are mounted on the track of an associated railcar for moving the railcar door therealong.
An operating mechanism is operably connected to the drive mechanism for selectively imparting rotation thereto. The operating mechanism comprises a shaft rotatably supported on the front surface of the sheet member and an activating member, such as a handle, secured to the shaft. A pair of transmission members are connected at a first end to the drive mechanism and at a second end to one of the elongated support members.
The drive mechanism may comprise a gear segment having a lobe. This gear segment is mounted on a bearing plate located on the sheet member. The drive mechanism further includes a pair of operating cams operably connected to both the gear segment and the transmission members.
The retarder assembly comprises a pin and a retarder block. The retarder block is attached to an upper corner of the bearing plate via the pin extending through openings in both the retarder block and bearing plate. The retarder block is captured between the bearing plate and a cover plate which is parallel to and spaced apart from the bearing plate. Preferably, the retarder block is fabricated from urethane or another hard, compressible material.
Rotation of the activating member or handle rotates the gear segment, thus causing rotation of the transmission and support members. The gear segment rotates until the lobe contacts and then compresses the retarder block, thus preventing further rotation of the gear segment.
A principal advantage of the present invention resides in the provision of an anti-drift retarding device for restricting a movable door from undesired and uncontrolled drifting into the side of an associated railcar.
Another advantage of the invention is found in the provision of an anti-drift retarder that enables the door to slide along a door track with minimal difficulty.
Yet another advantage of the present invention is the provision of an anti-drift retarder that helps prevent damage to a door and/or the side of a railcar due to door drifting.
Still another advantage of the invention resides in the provision of an anti-drift retarder that is relatively low in cost.
Yet another advantage of the invention is the provision of an anti-drift retarder that is easy to manufacture and retro-fit onto existing railcar doors.
Still other benefits and advantages of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed specification.